Full term newborns are in a state of relative vitamin K deficiency. Only recently, the vitamin K status of full term infants has been reliably described. Similiar information on premature infants is not available. This pilot study is proposed to prospectively investigate the vitamin K status of premature infants especially the very low birth weight infants. A cohort of premature newborns will be enrolled. Their vitamin K status will be assessed by measuring plasma vitamin K concentrations, PIVKA II, osteocalcin, calcium, phosphate and alkaline phosphatase levels in their blood at birth (cord blood), two, and six weeks of age. In addition urine calcium, hydroxyproline and creatinine excretion will be measured at the same times. An assessment of their vitamin K intake will be made from their daily parenteral, formula and breast milk intake. Amount of vitamin K given at birth as prophylaxis will also be noted.